Arrangement for valve transmitters connected with a load-equalizing tube



May 2, 1933. R. URTEL 1,906,501

ARRANGEMENT FOR VALVE TRANSMITTERS CONNECTED WITH A LOAD EQUALIZING TUBEFiled Oct. 12, 1928 INVENTOR RUDOLF URTEL B TORNEY Patented May 2,1933

UNITED STATES,

RUDOLF URTEL, 0F BERLIN, GERMANY, ,ASSIGrNOR- TO TELEFUNKEN, GESELLSCHAIT TENT OFFICE FfiR DRAHTLOSE TELEGRAPHIEiM, B. 1-1., 0]? BERLIN,GERMANY, A CORPORATION OF GERMANY I ARRANGEMENT non VALVE mnansmr'rnnsCONNECTED wrrn- A LOAD-EQUALIZING TUBE Application filed October 12,1928, Serial No. 312,074, and in Germany October 17, 1927.

It is known in the prior art to provide valve transmitters whose workingpotential is supplied from a network, with load-compensating circuitmeans. The purpose of the latter is to cause the potential sourcetooperate upon a separate circuit during the spacing periods to preventload fluctuations of the supply when signalling. For it will ,beunderstood that such variations of the load are liable to occasionovervoltages, and this might endanger the operation of the transmitterequipment, not to mention this further circumstance that the workingpotential variations associated with-such load fluctuations often affectthe frequency of the transmitter wave. Such frequency alterations willarise when the transmitter valve connected with the supply line isoperated in what is known as a self-excitation scheme. The loadcompensating circuits customarily provided in practice to preclude loadfluctuations consist usually of one ormore dis charge tubes which areconnected in parallel with the same network, and whose internalresistance is controlled in dependence upon the keying in such a waythat during the keying intermissions or spaces the decrease in the loadof the network due to the interruption of the transmitter wave iscompensated by an increase in the load due to the load-compensator tube.

According to the present invention, the control of the load-compensatortube is to be effected automatically by the variation of the grid directcurrent in the transmitter tube. If the said load-compensator tubeconsists of a triode, the controlling action is produced by varying thegrid biasing potential of this load-compensating tube in accordance withthe variations in the direct current in the grid circuit of thetransmitter valve. Proper control of the load on the source by thevariations in the biasing potential results from thefact that the gridof the load-compensating tube is given a more negative biasing potentialwhen the transmitter valve is oscillating, and that the said bias isless negative or more positive whenever the oscillations cease. 7

One embodiment of the basic idea of the invention is illustrated in theaccompanying drawing. Referring to the latter, Sis thetransmittervalvein what is known as the three-point connection scheme, B theload-compensator tube. These two tubes are connected with the supplysource net work terminals/H1 H2. Keying is effected by the aid of key Twhich interrupts; the supply line to the transmitter tube S. Theload-compensating tube B is suitably united with the supply network byway of a re-' sistance R. The grid of the load-compensating tube isconnected with a resistance R which is included in the grid circuit ofthe transmitter valve. As can be seen readily from the diagram, avoltage drop will occur across the resistance Rg when T is closed andtube Sand associated circuits'are in the state of oscillation, and as aresult a negative-biasing potential is impartedto the grid of theload-compensating tube B, with the consequence that the internalresistance of this tube becomes very high, whereas with opened keythevoltage drop across resistance R and thus also the biasing potential atthe load-compensating tube B disappear. By choosing suitable dimensionsfor the tubes and the resistance itis possible to create conditions sothat the load on the supply network remains unvaried whether thetransmitter is working or whether spacing occurs. In order that theradio frequency currents inthe grid cir cuit may not cause anyadditional control of the load-compensating tube, a condenser K isconnected in parallel relation with resistance R for the object ofcreating a shortcircuit for the radio frequency currents.

The arrangement here disclosed has proved satisfactory and isparticularly valuable for short-wave transmitters.

I claim:

1. In an oscillation system, an electron discharge tube having an inputcircuit and an output circuit, a power supply system for supplyingenergy to said tube, a second electron discharge tube having an inputcircuit and an output circuit said second mentioned tube being alsoconnected to said power supply system and means common to and both saidinput circuits for affecting the conductivity of said second mentionedtube in accordance with conditions in said first mentioned tube.

2. Ina system of the kind described, an oscillation generator comprisinga space discharge device having input and output circuits, a powersupply circuit for said space discharge device, a load compensatormeans, comprising a second space discharge device having input andoutput circuits, and means common to said mentioned input circuits foraflecting said second named space discharge device in opposite sensetoconditions in said first mentioned electron discharge device. a

3. In an oscillation system an electron discharge device having an inputcircuit and an output circuit, a power supply system for supplyingenergy to said device, a

variable loading device shunted across said power supply system andmeans in said in put circuit for controlling said variable loadingdevice in accordance with the load placed upon said power supply systemby said electron discharge device in opposite senses whereby the totalload on said system remains constant.

4. In a signal transmission system, means for generating high frequencyoscillations, comprising an electron discharge device having an inputcircuit and an output circuit, a resistance in said input circuit, apower supply system for said space discharge device, a load compensatormeans comprising a second electron discharge device having its anode andcathode circuit connected across said power supply system and its gridand cathode circuit connected across said resistance, signal modulatingmeans assooiated with said oscillation generator and means controlledthereby for affecting the conductivity of said second electron dischargedevice.

5. In combination, an electron discharge device having high frequencyinput and output circuits, a resistance in series with the grid of saiddevice, a condenser across said resistance for preventing the flow ofhigh frequency currents in said resistance, a source of potentialconnected to other electrodes of said device, a vacuum tube connectedacross said source, and means connecting said resistance to said vacuumtube whereby the conductivity of said tube is varied in accordance withthe unidirectional potential difference across said resistance.

6. In apparatus of the character described, the combination of anelectron discharge device having an anode a cathode and a grid, saiddevice having in addition high frequency input and output circuits, aresistance in series with the grid of said device, a relatively largecapacity condenser shunting said resistance, a source of potential forsupplying anode potential to the anode of said device, a tube having ananode a cathode and a grid connected across said source, said lastmentioned. grid being connected to said resistance whereby theconductivity of said tube is varied in accordance with the potentialdifference across said resistance thereby maintaining the anodepotential applied to said electron discharge device substantiallyconstant despite variations in high trequenc load thereon.

7 he combination in a signal system of an electron discharge devicehaving an anode, a cathode, and an output circuit associated with saidanode, means for producing oscillations on the grid of said dischargedevice in accordance with desired signals whereby said oscillations aresupplied to saidoutput circuit, a source of electromotive forceconnected between said anode and cathode, the magnitude of oscillationssup plied to said load circuit being dependent upon the electromotiveforce supplied to said anode, a second electron discharge device havingan anode and cathode connected in shunt with the anode and cathode ofsaid first device and arranged normally to draw appreciable current fromsaid source, and means responsive to oscillations on the grid of thefirst device for alternately transferring a portion of the load on saidsource from one of-said devices to the other, thereby to preventvariations of potential in said source due to changes in magnitude ofload thereon.

8. In a signalling system, an electron dis charge device having inputand output electrodes and input and output circuits connected therewith,means for connecting the output electrode of said discharge device to asource of energizing current including a key, and means for maintaininga constant load on said source irrespective of the conductivity of saidtube as determined by the position of said key comprising, a second adischarge device having its anode to cathode impedance connected inparallel with said source, said second discharge device having a controlelectrode, and means connected with said control electrode and with oneof said circuits to apply energy from one of said circuits to saidcontrol electrode, the amount of which is determined by the position ofsaid key.

RUDOLF URTEL.

